Getting started with OSL

Install OSL, set your password, and send your first encrypted message.

Install OSL #

Download OSL from the download page and run the installer.

On first launch, Windows may show a SmartScreen warning that says "Windows protected your PC." This is expected — OSL is a new application from an independent developer. Click "More info" and then "Run anyway." See the explanation on the download page for the full story.

OSL replaces your Discord desktop client. After install, you'll launch OSL instead of Discord, but Discord works the same way inside it.

Set your password #

The first time you launch OSL, you'll be prompted to set a password. This password encrypts your keys and message history on your computer.

OSL requires at least 6 characters — longer is stronger. There is no password recovery. If you forget your password, all your encrypted history becomes permanently inaccessible.

Write your password down somewhere safe. A password manager works. A piece of paper in a drawer works. What doesn't work is "I'll remember it."

Whitelist your first friend #

Both you and your friend need OSL installed to exchange encrypted messages. After both of you have OSL running, you can whitelist each other.

To whitelist someone, click their name in any channel to open their profile, then click "Whitelist for OSL." Once they whitelist you back, encryption is enabled between you.

For bulk whitelisting in a server or channel, right-click the channel header's lock icon and choose "Whitelist channel members."

Send your first encrypted message #

Type as you normally would in Discord. OSL encrypts the message before sending. The lock icon in the channel header turns green when encryption is active.

Your friend, also running OSL, sees your message decrypted automatically. Anyone reading the raw Discord messages — including Discord itself — sees ciphertext only.

What if your friend doesn't have OSL? #

If you send an encrypted message to someone without OSL, they'll see what looks like random base64 garbage — that's the ciphertext, undecryptable without OSL installed and the right keys.

You have two options: install OSL together with them, or send them an unencrypted message by clicking the lock icon to temporarily disable encryption for that message.

You'll get a clear visual indicator before sending an unencrypted message so it doesn't happen by accident.